There is a growing need in the textile market for siloxane fabric softeners that not only provide softening but also impart hydrophilicity and other desirable properties to the treated fabric. Using a conventional siloxane polymer as the active ingredient in a fabric treatment agent often requires a trade-off in properties.
Amine-functional polysiloxanes are known to improve the hand of textiles. `Hand` means the softness and smoothness of the textile. The hand of a treated textile is directly related to the amine content (e.g., the number of amino-functional groups) of the polysiloxane. Generally, as the amine content increases, the hand of the textile improves.
One method to produce amine-functional siloxane compounds for use as fabric treatment agents is to react an epoxy-functional silicone with an amine-functional organic compound. This method is described in U.S. Pat. No. 4,409,267 to Ichinohe et al., Oct. 11, 1983. The organopolysiloxane is prepared by a process comprising: 1) reacting a silanol-functional organopolysiloxane with a polyoxyalkylene compound and an epoxy-functional compound, by addition reaction, and thereafter 2) reacting an amine compound with the epoxy group of the epoxy-functional organopolysiloxane. The reactions are typically carried out in the presence of a solvent. The solvent and any impurities formed during reaction must then be removed.
U.S. Pat. No. 5,593,611 to Czech, Jan. 14, 1997, discloses a fabric treatment composition comprising an aminopolysiloxane. The aminopolysiloxane is prepared by hydrolyzing and condensing an amino-functional dialkoxysilane with water in the presence of heat and a base catalyst. The aminopolysiloxane is hydrophobic and has a molecular weight of at least 30,000.
U.S. Pat. No. 4,757,121 to Tanaka et al., Jul. 12, 1988, discloses a fiber softening composition for synthetic fibers. The composition contains a combination of 2 different amino-substituted organopolysiloxanes, an epoxy-substituted alkoxysilane, and a monoepoxy compound. The first amino-substituted organopolysiloxane is terminated with a hydroxy group or alkoxy group that reacts with the epoxy-containing alkoxysilane. This forms a film of a crosslinked composition on the fiber surface. The second amino-substituted alkoxysilane is trialkyl-silyl terminated, and the second organopolysiloxane is prepared by reacting an amino-containing organopolysiloxane with a liquid organic epoxy compound.
U.S. Pat. No. 4,680,366 to Tanaka et al., Jul. 14, 1987, discloses a fabric finishing agent containing an organopolysiloxane with primary and secondary amine-functional hydrocarbon groups and polyoxyalkylene groups. The organopolysiloxane is prepared by reacting a polyoxyalkylene glycidyl ether with an aminofunctional organopolysiloxane.
However, the amine-functional polyorganosiloxanes suffer from the drawback that as the amine content of the polyorganosiloxane increases, the tendency of the textile to discolor or yellow increases, when the amine-functional polyorganosiloxanes are used in textile treatment compositions. Additionally, the amine-functionality tends to impart hydrophobicity to the treated textile.
To minimize yellowing, it has been the practice in the textile industry to impart softness to a textile by applying a modified polysiloxane, which contains amide groups or carbamate groups instead of amine groups. However, amide and carbamate groups do not provide the same desirable level of softness characteristic of the amine groups.
For example, another method for producing amine-functional siloxanes is disclosed in "Structure Activity Relationships of Aminofunctional Siloxanes as Components in Softening Finishes", Textile Chemist and Colorist, by Lautenschlager et al., published March 1995, Vol. 27, No. 3. Lautenschlager et al. disclose that epoxidation is not a viable alternative to an improved softener because of impurities formed during the reaction. Alternatively, Lautenschlager et al. disclose acylated aminofunctional silicones, and a method for their preparation by acylation of an aminofunctional silicone fluid. The acylating agent can be an anhydride, lactone, or carbonate. However, the resulting acylated aminofunctional silicones exhibit a decline in hand when compared to standard aminosiloxanes.
U.S. Pat. No. 5,100,991 to Cray et al., Feb. 22, 1996, discloses compounds that can be used in fabric treatment compositions. The compounds are prepared by reacting an aminofunctional silane or siloxane with a lactone.
U.S. Pat. No. 5,118,535 to Cray et al., Jun. 2, 1992, discloses a cyclic diamine functional polydiorganosiloxane that can be used in treating fibrous materials.
EP A2 0 399 706 by Cray, published on Nov. 28, 1990, discloses a method for preparing a treatment agent for fibrous materials. The method comprises pre-reacting an amine-containing organosiloxane with a monoepoxide. The resulting product has primary, secondary, and tertiary amine groups, where up to 10% of the amine groups are primary amine groups.
U.S. Pat. No. 4,311,626 to Ona et al., Jan. 19, 1982, discloses a fiber treatment composition containing an aminofunctional polydiorganosiloxane and a carboxylfunctional polydiorganosiloxane. However, carboxyl groups detrimentally affect the hand of the treated fibers.
However, none of these references disclose a siloxane copolymer having amine-, polyol-, and amide-functional groups. Therefore, it is an object of this invention to provide an amine-, polyol, amide-, dimethyl-functional siloxane copolymer. It is a further object of this invention to provide an amine-, polyol-, amide-, dimethyl-functional siloxane copolymer that can be used in fiber treatment compositions.